Portable power charging of implantable medical devices

ABSTRACT

An implantable medical device, comprising an implantable component having a rechargeable power supply and an external wireless charger. The wireless charger has a rechargeable power supply, and an inductive coil configured to transcutaneously transfer power from the charger power supply to the implantable power supply, and configured to detect and receive, via the inductive coil, power from an auxiliary charger for recharging of the charger power supply.

BACKGROUND

1. Field of the Invention

The present invention relates generally to implantable medical devices,and more particularly, to portable power charging of implantable medicaldevices.

2. Related Art

Medical devices having one or more implantable components, generallyreferred to herein as implantable medical devices, provide a wide rangeof therapeutic benefits to recipients. Certain implantable medicaldevices, sometimes referred to as active implantable medical devices(AIMDs), include an implantable power supply that provides power to oneor more implantable components. AIMDS include, but are not limited to,certain implantable hearing prostheses, neural stimulators, drug pumpsand cardiac devices.

One type of hearing prosthesis that is widely used is the partiallyimplantable cochlear implant. Traditionally, partially implantablecochlear implants consist of an external speech processor unit and animplanted receiver/stimulator unit. The external speech processor unitis worn on the body of the user, such as a behind-the-ear (BTE) device.BTE devices are generally configured to receive sound with a sound inputelement, such as a microphone, and to convert the received sound into anelectrically coded data signal that is transcutaneously transferred tothe implanted receiver/stimulator unit. The BTE device is also generallyconfigured to transcutaneoulsy transfer power to the implanted receiverand stimulator unit. More particularly, the power and data aretranscutaneously transferred via a magnetic induction link establishedin a reactive near-field between an external coil closely coupled to animplanted coil.

Traditionally, the operating power for the BTE device and implantedcomponents is provided by batteries, such as Zn-Air batteries, housed inthe device. The closely coupled coils include an external coil coupledto the BTE device which is configured to be placed in close proximity tothe coil of the implanted component. However, due to improvements inpower storage technology, it has become more common for implantablehearing prosthesis and other AIMDs to include an implantable powersupply that is sufficient to allow for periods of operation withoutaccess to an external power source. Such implantable power storage hasenabled certain devices, in particular hearing prostheses, to becometotally or fully implantable.

In addition to an implantable power supply, totally implantable hearingprostheses also have one or more components that were traditionallyexternal to the recipient, such as the sound processor, implantable inthe recipient. Accordingly, totally implantable prostheses to operateindependently (that is, without an external device) for periods of time.It would be appreciated that, as used herein, totally or fullyimplantable hearing prosthesis may include external devices such asmicrophones, remote controls, etc.

Various implantable power storage systems have been proposed. However,in all implantable systems it remains necessary to transfer power froman external power supply to recharge the implanted power storage system.Devices continue to use the closely coupled external/internal coils totransfer the power, although the headpiece coil is not continuouslyrequired for regular operation. Data transfer may occur usingalternative wireless links, for example short range EM(electro-magnetic) links (e.g. 400 MHz) or MI (magnetic induction) links(e.g. 10.7 MHz).

SUMMARY

In one aspect of the present invention, an implantable medical system isprovided. The system comprises: an implantable component having arechargeable power supply; and an external wireless charger having arechargeable power supply, and an inductive coil configured totranscutaneously transfer power from the charger power supply to theimplantable power supply, and configured to detect and receive, via theinductive coil, power from an auxiliary charger for recharging of thecharger power supply.

In another aspect of the present invention, a method for operating acochlear implant comprising an implantable component having arechargeable power supply, an external wireless charger having arechargeable power supply and an inductive coil, and an auxiliarycharger is provided. The method comprises: transmitting power from thecharger power supply to the implantable power supply with the inductivecoil; disabling transmission of power from the charger power supply tothe implantable power supply; and checking for at least one of thepresence and absence of the auxiliary charger or implantable componentwhile the transmission of power from the charger power supply to theimplantable power supply is disabled.

In a still other aspect of the present invention, a cochlear implant isprovided. The cochlear implant comprises: an implantable componenthaving a rechargeable power supply; an external auxiliary charger; andan external wireless charger having a rechargeable power supply, and aninductive coil configured to transcutaneously transfer power from thecharger power supply to the implantable power supply, and configured todetect and receive, via the inductive coil, power from the auxiliarycharger for recharging of the charger power supply.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are described below with referenceto the attached drawings, in which:

FIG. 1A is a schematic diagram of a cochlear implant, in accordance withembodiments a of the present invention;

FIG. 1B is a schematic diagram illustrating exemplary externalaccessories that may be implemented in accordance with embodiments ofthe present invention;

FIG. 2 is a schematic block diagram of a wireless charger, in accordancewith embodiments of the present invention;

FIG. 3 is a schematic diagram illustrating one implementation of anauxiliary charger, in accordance with embodiments of the presentinvention;

FIG. 4 is a schematic diagram illustrating of a cochlear implant system,in accordance with embodiments of the present invention;

FIG. 5 is a schematic diagram of a wireless charger having the coilintegrated in its housing, in accordance with embodiments of the presentinvention;

FIG. 6 is a block diagram of an alternative implementation of a wirelesscharger, in accordance with embodiments of the present invention;

FIG. 7 is a flow chart of a charging process for a wireless charger, inaccordance with embodiments of the present invention;

FIG. 8 is a timing diagram corresponding to the method illustrated inFIG. 7;

FIG. 9A is a perspective view of a wireless charger, in accordance withembodiments of the present invention; and

FIG. 9B is a perspective view of a wireless charger, in accordance withembodiments of the present invention; and

DETAILED DESCRIPTION

Aspects of the present invention are generally directed to animplantable medical device or system having a implantable power supplythat receives power from wireless charger worn by a recipient of thedevice. The wireless charger also includes a rechargeable power supply,and is configured to transcutaneously transfer power to the implantablepower supply. The wireless charger is also configured to receive powerfrom an auxiliary charger. In certain embodiments, the wireless chargerincludes one inductive coil that is used to both receive and transmitpower.

Embodiments of the present invention will be described with reference toa particular illustrative implantable medical system, namely a cochlearimplant system, commonly referred to as a cochlear prosthesis or simplycochlear implant. It would be appreciated that embodiments of thepresent invention may be implemented in other medical systems utilizingor requiring periodic transfer of power via an indicative link.Exemplary devices include, but are not limited to, neural or musclestimulators, drug pumps, cardiac devices, and other hearing prosthesissuch as hybrid electrical/acoustic systems, acoustic hearing aidsystems, middle ear stimulators, or fully external hearing systems, etc.

FIG. 1A is a schematic diagram of a cochlear implant 100 in accordancewith embodiments of the present invention. As shown, cochlear implant100 comprises an implantable component 104 positioned below arecipient's skin and other tissue (not shown), and external component(s)102. In the embodiment of FIG. 1A, external component(s) 102 comprise awireless charger 110, and an external accessory 106. Further details ofwireless charger 110 and external accessory 106 are provided below.

As shown, wireless charger 110 includes to a radio frequency (RF)headpiece coil 112. Headpiece coil 112 is configured to be inductivelycoupled to RF coil 116 in implantable component 104 via inductive link132. Implantable coil 116 is connected to a transceiver unit 128.

As shown, implantable component 104 also includes an implantable powersupply, shown as a rechargeable battery unit 118, a stimulator unit 120,an intracochlear electrode assembly 122 and one or more supplementaryextracochlear ground electrode(s) 124. In the embodiments of FIG. 1A,transceiver 128, battery unit 118 and stimulator unit 120 are positionedin a hermetically sealed housing 130. Implantable component 104 alsoincludes an electronics module 114 that may comprise, for example, asound processor, memory, controller, etc.

In the embodiments of FIG. 1A, a separate implantable microphone 126 isalso provided. Microphone 126 may be electrically coupled to one or morecomponents in housing 130 via a cable/lead, or via a wireless link 144.

In embodiments of the present invention, wireless charger 110 includes arechargeable power supply, sometimes referred to herein as charger powersupply or battery system 134. In certain embodiments, battery system 134comprises one or more rechargeable batteries 134. Although for ease ofdiscussion the term battery system us used to refer to the power supplywithin the charger, it would be appreciated that any rechargeable powersource that is able is sufficiently small and is able to fulfill thepower requirements of the device may be used. For example, in certainembodiments, a Li-ion or Li-polymer battery unit is used. As is known inthe art, such batteries may be shaped to fit perfectly in housingshaving different geometries. In other embodiments, nickel cadmium, metalhydride, a supercapacitor based system or even energy stored in a springwound up by a clockwork mechanism may used.

Wireless charger 110 is configured to provide power from battery system134 to implantable battery unit 118. The power is inductivelytransferred via link 132. As described further below, battery system 134of wireless charger 110 is recharged by receiving power from anauxiliary charger via headpiece coil 112.

As previously noted, one or more external accessories 106 may also beworn by the recipient and may communicate with implantable component104. Specifically, an external accessory 106 is a device thatcommunicates with implantable component 104 via a low-power wirelessdata link 140. In certain embodiments, an external accessory 106includes a microphone and/or sound processor. Exemplary externalaccessories 106 are schematically shown in FIG. 1B as a mini-BTE (106A),micro-BTE (106B), in-the-ear (ITE) device (106C), an in-the-canal (ITC)device (106D), open-fit or over-the-ear device (OTE) (not shown), orother device. Exemplary data links are described in US PatentApplication US2008/0300658, the contents of which are herebyincorporated by reference herein. FIG. 9A is a perspective view of awireless charger 910A that is a BTE device. Similarly, FIG. 9B is aperspective view of a body worn charger 910B.

FIG. 1A illustrates embodiments of the present invention in whichwireless charger 110 and external accessory 106 are separate components.It would be appreciated that in embodiments of the present invention,external accessory 106 and wireless charger 110 may comprise the samecomponent. For example, in embodiments of the present invention, a BTEdevice may operate as the wireless charger and may include components ofan external accessory, such as a sound processor, microphone etc.

FIG. 2 is a schematic block diagram of an implementation of an wirelesscharger 110 of FIG. 1A. As shown, charger 110 includes a power supply,such as rechargeable battery system 134. To transfer power toimplantable component 104 (FIG. 1), power from battery system 134 isprovided to DC/AC converter 240, that then provides an AC waveform todriver 242. The AC waveform may be modulated for transfer of data toimplantable component 104 via link 132 (FIG. 1), or if spreading of thefrequency spectrum is desired to reduce dense spectral power components(EMC). Driver 242 amplifies the waveform to a suitable signal level forpower transfer to implantable component 104. The amplified signal fromdriver 242 is provided to routing system 244, which controls the flow ofpower to and from coil 50. Specifically, routing system 244 isconfigured to function as a coupler/splitter for signals received fromdriver 240 and coil 112. Routing system 244 may include components fordriving coil 112 to transmit the power signals to implantable component104.

As previously noted, coil 112 in wireless charger 110 is used toinductively transfer power to implantable component 104, and to receivepower from auxiliary charger 350. Using the same coil for bothtransmission and receipt of power simplifies the manufacturing processand enhances friendliness and simplicity of use. Accordingly, wirelesscharger 110 receives power from an auxiliary charger via coil 112 andthe received power is routed from the coil to battery recharger 246 andbattery system 134.

FIG. 3 is a perspective view of one implementation of an auxiliarycharger 350 in accordance with embodiments of the present invention. Asshown, auxiliary charger 350 comprises a base 352 on which an array ofcoils 354A, 354B and 354C is positioned. Attached to base 356 is a plug356 for connecting auxiliary charger 350 to a 12V power source, DC powersupply (e.g., in a car), or other power sources. In operation, whenwireless charger 110 is in proximity to auxiliary charger 350, one ofthe coils 354A, 354B, or 354C is inductively coupled to coil 112. Byhaving an array of coils 354A-C, rather than only one coil, the systemmakes it easier for a recipient to couple chargers 110 and 350.Specifically, the array of coils increases the likelihood that therecipient will be able to position the wireless charger 110appropriately so that an inductive link is formed between coil 112 and acoil 354. When wireless charger 110 is fully charged, auxiliary charger350 and the wireless charger may be separated.

It would be appreciated that auxiliary charger 350 may have a variety ofarrangements. For example, auxiliary charger 350 may be a charging pad,a cradle, a docking station, or any suitable arrangement. Auxiliarycharger 350 may also be adapted to charge other devices, for example anyexternally worn microphone or remote control units.

FIG. 4 is a schematic diagram illustrating wireless links betweenauxiliary charger 350, wireless charger 110 and implantable component104. As would be appreciated, the links shown in FIG. 4 are merelyillustrative any additional links could be provided. Alternatively, allof the links shown in FIG. 4 are not necessary and one or more links maybe omitted in different configurations.

As shown in FIG. 4, a wireless power link 464 is provided between a coil354 (FIG. 3) in auxiliary charger 350, and headpiece coil 112.Additionally, a feedback link 462 is provided to transmit datainformation between auxiliary charger 352 and wireless charger 110. Forexample, link 462 may used by wireless charger 110 to instruct auxiliarycharger 350 to adjust link 464, or to adjust other characteristics ofthe auxiliary charger.

Also as shown in FIG. 4, link 132 is provided between implantable coil116 and headpiece coil 112 to transmit power from wireless charger 110to implantable component 104. In certain embodiments, a bidirectionaldata link 466 may also be provided between coils 112, 116 to transmitdata to or from implantable component 104.

As noted above, in embodiments of the present invention a wirelesscharger also operates as an external accessory. That is, the wirelesscharger includes components of an external accessory, such as a soundprocessor, microphone, control electronics, etc. In such embodiments, anadditional data link may be provided between the wireless charger andthe implantable component. However, in certain embodiments, the wirelesscharger is a simple charging arrangement that does not otherwiseinteract with the implantable component.

FIG. 5 is schematic diagram of an alternative cochlear implant 500 inaccordance with embodiments of the present invention. As shown, cochlearimplant 500 comprises an implantable component 504 that is substantiallythe same as implantable component 104 of FIG. 1. Cochlear implant 500further comprises a wireless charger 510. As shown, wireless charger 510has a coil 512 wireless charger in its housing 514.

Also shown in FIG. 5 are exemplary magnetic flux lines 520 generated bycoil. As shown, magnetic flux lines 520 pass through implantable coil516, thereby inductively coupling coil 512 to coil 516.

As noted above, FIG. 3 is a schematic block diagram of one embodiment ofwireless charger 110 of FIG. 1. FIG. 6 is a schematic block diagram ofan alternative wireless charger 610 having a controller 670 to managerecharging and communications of the charger. Charger 610 has componentsthat are substantially the same as described above with reference toFIG. 3, including batteries 634, DC/AC converter 640, driver 642,routing system 644, and battery recharger 646. However, as shown in FIG.7, wireless charger 610 includes several components, namely powerdetector 672 and controller 670, that are not found in wireless charger110 of FIG. 3. As described below, the power emanating from wirelesscharger unit 610 is provided to the implantable component 104. Theauxiliary power emanating from auxiliary charger 350 (FIG. 3) isprovided to wireless charger unit 610 to charge the batteries therein orthereon.

For ease of description, the operation of controller 670 will describedwith reference to the control process 700 of FIG. 7.

Control process begins at block 704 after the wireless charger ispowered ON at block 702. More particularly, at block 704 controller 670of wireless charger 610 initially operates the primary power link for atime duration T1. The primary power link is the link between externalcoil 612 of wireless charger 610 and the implantable coil. At block 706,controller 670 disables primary power link for a time duration T2, andmonitors for the presence of the auxiliary charger. In certainembodiments, T2 is preferably is relatively short when compared to T1.Referring to the embodiments of FIG. 6, the presence of the auxiliarycharger may be detected by power detector 672. It should be noted thatin certain embodiments the primary power link is disabled for a shorttime at block 706 to allow detection (presence or absence) of auxiliarypower sources or implantable components.

At block 708, controller 670 performs a check to determine if theauxiliary charger is detected. If the auxiliary charger is not detected,control process 700 returns to block 704 where controller 670 againenables primary power link for T1. This process continues until theauxiliary charger has been detected.

When the auxiliary power source is detected, control process 700continues to block 710 where controller 670 performs a check of whetherthe battery is fully charged. If the battery is not fully charged,controller 670 activates the auxiliary link (that is, the link betweenthe wireless charger and the auxiliary charger), and the battery(ies) ofthe wireless charger are recharged at block 712. If, at block 710, it isdetermined that the battery(ies) are fully charged, control process 700returns to block 704. It would be appreciated that control process 700of FIG. 7 is one implementation, and other methods for managing wirelesscharger and the dual purpose coil and associated systems may beimplemented in alternative embodiments of the present invention

FIG. 8 is a timing diagram schematically illustrating how certaincomponents of wireless charger 610 are operated during control process700.

Specifically, FIG. 8 shows the output 680A of power detector 672, theinput 680B of DC/AC converter 640, and the output 680C of batteryrecharger 646 during times T1 and T2. As shown, when power is beingprovided via the primary link, input 680B of DC/AC converter 640 ishigh, while output 680C of battery recharger 646 is low (that is,battery recharger 646 is disabled). As noted above, controller 670monitors for the presence of the auxiliary charger during times T2.

In one embodiment shown in FIG. 4 a wireless backlink 466 from theimplantable component 104 to the wireless charger 110, for examplesimilar to the telemetry systems known for cochlear implants, providesthe type of implantable component and status information on the state ofthe implanted rechargeable battery to the recharger during its chargingand discharging cycle. The wireless back link is optional and could beoperating over the same or a different RF frequency channel. In case theRF frequency channel is shared a TDMA scheme becomes necessary. In bothcases the system requires additional communication blocks. As analternative to TDMA load modulation could be applied by switching on andoff a small load resistance on the BTE charger. This would result in avoltage variation over the auxiliary coil such as in amplitudemodulation.

All references referred to in the specification are hereby incorporatedby reference into this disclosure. Many variations and additions arepossible within the general inventive scope

The invention claimed is:
 1. An implantable medical system, comprising:an implantable component having an implantable power supply; and anexternal wireless charger having a charger power supply, a driver, aninductive coil, a battery recharger, and a routing system connectedbetween the driver, the inductive coil, and the battery recharger,wherein the routing system has a first configuration that passes signalsfrom the driver to the inductive coil in order to transcutaneouslytransmit power from the charger power supply to the implantable powersupply via the inductive coil, and wherein the routing system has asecond different configuration that passes power received from anauxiliary charger at the inductive coil to the battery recharger forrecharging of the charger power supply.
 2. The medical system of claim1, further comprising a power detector, wherein the inductive coil ofthe external wireless charger is connected to the power detector, andthe power detector is configured to periodically determine whether theauxiliary charger is capable of supplying power sufficient to rechargethe charger power supply.
 3. The medical system of claim 1, wherein theexternal wireless charger is a Behind-the-Ear (BTE) device.
 4. Themedical system of claim 1, wherein the external wireless charger is abody worn device.
 5. The medical system of claim 1, wherein an energystorage capacity of the charger power supply is larger than an energystorage capacity of the implantable power supply.
 6. The medical systemof claim 1, wherein the external wireless charger has a housing, andwherein the inductive coil is separated from the housing by a cable. 7.The medical system of claim 1, wherein the external wireless charger hasa housing, and wherein the inductive coil is integrated into thehousing.
 8. The medical system of claim 1, wherein the external wirelesscharger is configured to: sense the presence of an inductive fieldsuitable for recharging the charger power supply; and in response tosensing the presence of the inductive field, switch to automaticallyrecharge the charger power supply.
 9. The medical system of claim 1,further comprising: an external accessory configured to transcutaneouslytransmit data to the implantable component.
 10. The medical system ofclaim 9, wherein the external accessory comprises a microphone and asound processor.
 11. The medical system of claim 1, wherein the externalwireless charger is further configured to transcutaneously transmit datato the implantable component via the inductive coil.
 12. The medicalsystem of claim 11, wherein the external wireless charger comprises amicrophone and a sound processor.
 13. The medical system of claim 1,further comprising: the auxiliary charger.
 14. The medical system ofclaim 13, wherein the auxiliary charger comprises an array of inductivecoils for transmitting power to the external wireless charger.
 15. Themedical system of claim 9, wherein the external wireless charger isconfigured to transmit power to the external accessory via the inductivecoil.
 16. The medical system of claim 1, further comprising a powerdetector configured to detect the presence of the auxiliary charger. 17.A method for operating a cochlear implant comprising an implantablecomponent having an implantable power supply, an external wirelesscharger having a charger power supply, a driver, an inductive coil, abattery recharger, and a routing system connected between the driver,the inductive coil, and the battery recharger, the method comprising:providing, via the routing system, power signals from the driver to theinductive coil; transmitting, based on the power signals received viathe routing system, power from the charger power supply to theimplantable power supply via the inductive coil; disabling, using therouting system, transmission of power from the charger power supply tothe implantable power supply; wirelessly receiving, via the inductivecoil, power from an auxiliary charger; and providing, via the routingsystem, the power received from the auxiliary charger to the batteryrecharger to recharge the charger power supply.
 18. The method of claim17, further comprising: checking for at least one of the presence andabsence of the auxiliary charger or implantable component, while thetransmission of power from the charger power supply to the implantablepower supply is disabled.
 19. The method of claim 18, wherein receivingpower from the auxiliary charger comprises: determining that theauxiliary charger is present; activating a wireless link between theauxiliary charger and the wireless charger, wherein the wireless link isformed by the inductive coil and a coil in the auxiliary charger; andreceiving, with the inductive coil, power from the auxiliary charger forrecharging of the charger power supply.
 20. The method of claim 19,further comprising: determining whether the charger power supply isfully charged prior to activating the wireless link between theauxiliary charger and the wireless charger.
 21. A cochlear implantsystem, comprising: an implantable component having an implantable powersupply; an external auxiliary charger; and an external wireless chargerhaving: a charger power supply, a driver, a battery recharger, aninductive coil, and a routing system connected between the driver, theinductive coil and the battery charger wherein the routing system passessignals from the driver to the inductive coil in order totranscutaneously transmit power from the charger power supply to theimplantable power supply via the inductive coil and wherein the routingsystem; and passes power received from the auxiliary charger at theinductive coil to the battery recharger for recharging of the chargerpower supply.
 22. The cochlear implant system of claim 21, wherein anenergy storage capacity of the charger power supply of the externalwireless charger is larger than an energy storage capacity of theimplantable power supply of the implantable component.
 23. The cochlearimplant system of claim 21, wherein the external wireless charger has ahousing, and wherein the inductive coil is separated from the housing bya cable.
 24. The cochlear implant system of claim 21, wherein theexternal wireless charger has a housing, and wherein the inductive coilis integrated into the housing.
 25. The cochlear implant system of claim21, wherein the external wireless charger is configured to: sense thepresence of an inductive field suitable for recharging the charger powersupply of the external wireless charger; and in response to sensing thepresence of the inductive field, switch to automatically recharge thecharger power supply of the wireless charger.
 26. The cochlear implantsystem of claim 21, further comprising: an external accessory configuredto transcutaneously transmit data to the implantable component.
 27. Thecochlear implant system of claim 21, wherein the external wirelesscharger is further configured to transcutaneously transmit data to theimplantable component.
 28. The cochlear implant system of claim 21,further comprising a power detector configured to detect the presence ofthe auxiliary charger.